In many photographic applications it is necessary to provide a means for readily dispensing photosensitive material in an apparatus, such as a photographic printer. This requires that some means be provided in which the photosensitive material can be transported to the apparatus in a light tight environment, and conveniently inserted into the apparatus in ambient light conditions. One way of accomplishing this is to provide clamshell-type cassettes. These cassettes have a lower partially cylindrical section, and an upper partially cylindrical section which mate along a common hinge on a first lengthwise edge of each and the second lengthwise edge of each of which abut one another when the cassette is closed. This provides a light tight housing when closed. Seats are provided inside the cassette which allow the web roll to rotate as desired. Pivoting of one section about the hinge, with respect to the other, opens the cassette and allows a web to be inserted into the cassette in a safelight environment. The loaded cassette can then be closed and safely transported to the equipment where it is to be used. Generally, the apparatus in which the web is to be used allows the cassette to be loaded into a chamber of the apparatus in ambient light conditions, then mechanically opens the cassette following closure of a light tight door on the apparatus.
A difficulty with a clamshell type cassette is that pivoting of the one section requires that the apparatus have sufficient room in the cassette chamber to accommodate the increasing space required by the cassette opening. This results in a relatively bulky apparatus simply to accommodate this opening motion. Another cassette is that of the type disclosed in U.S. Pat. No. 2,298,329 or U.S. Pat. No. 3,550,882. In these cassettes one partially cylindrical section rotates inside another to expose an opening, and the photosensitive web is apparently loaded into the cassette in an axial direction following removal of an end of the cassette. Such a disassembly procedure is tedious. Further, the opening is opened during dispensing of web material which allows film inside the cassette to be exposed to stray light inside the apparatus over all the time the cassette is in use. Another difficulty with clamshell cassettes is that when completely open to load a web roll, they can be relatively unstable due to a raised center of gravity. This can cause the clamshell to be readily knocked over particularly in a darkroom environment in which loading occurs.
It would be desirable then to provide a cassette which has a simple means of allowing loading of a photosensitive web roll, which is relatively stable when open for loading, which does not require significant extra space inside an apparatus just to accommodate cassette opening, and which can dispense photosensitive web material in such a way that web material inside the cassette has little exposure to stray light over the time the cassette is in use.